EP1217246B2 - Brake pad for disc brakes - Google Patents

Abstract

A brake pad, preferably used disc bakes, comprises a profiled metal back plate, to which at least one friction lining is attached, characterized in that a material with lower heat conductivity, relative to the friction lining, is provided in at least some profile sections.

Description

The invention relates to a brake shoe, in particular for disc brakes, including a provided with profiles metallic back plate on which at least one friction lining is attached.

Of the DE-A 197 06 123 is to take such a brake shoe, wherein the back plate in the circumferential direction has at least two sections with different back plate thickness. The shapes should in this case be designed so that they also relieve the thermal stress of the brake shoe bringing into operative engagement actuator. Described are corrugated profiles, rectangular profiles, indentations, beads or the like. Even if a certain amount of thermal relief or decoupling can already be achieved here, unwanted temperatures in the region of the actuating element, in particular the brake cylinder or its peripheral components, which can cause damage, nevertheless become effective at increased braking forces.

Of the US-A 6,041,893 is to remove a brake shoe, including a metallic back plate and a friction lining mounted thereon. Between friction lining and back plate extends at least one additional layer, which are assigned to certain damping properties and which also leads to acoustic warnings when the friction lining is worn.

EP 0503625 A discloses a brake shoe for a disc brake with a metal backing plate to which a friction material block is connected. Between the back plate and the friction lining a heat insulating layer of ceramic is arranged, which is applied over the entire surface by a plasma spraying process. In one embodiment, a rectangular recess in the back plate is provided, which serves together with a web with approximately dovetailed contour for attachment of the brake lining to a brake caliper, so that there is a constant material thickness.

In US 4685543 A is described a support plate for a brake pad, which is formed of a thin layer of corrosion-resistant material. The carrier plate has a recessed, substantially circular area, which corresponds to the shape of the brake piston. In the recessed area, a thermal barrier is formed by an air gap between the base member and the brake cylinder.

In addition, in DE 1600155 A a brake pad carrier for disc brakes described in which an additional plate or a sheet is firmly attached to the support plate of the brake pad to reduce the noise and to achieve the most uniform pad wear. The friction lining material is in direct contact with the carrier plate.

The JP 57-90931 discloses a brake shoe according to the preamble of claim 1.

The invention has for its object to optimize a brake shoe according to generic part of the first claim so that caused by temperature damage to the actuating element, in particular brake cylinder or the cooperating peripheral components is avoided.

This object is achieved by a brake shoe according to claim 1.

Advantageous developments of the subject invention can be found in the dependent claims.

In development of the prior art, in particular the JP 5 790 931 , The subject invention allows a significant decoupling of the heat flow between friction lining and actuator, in particular brake cylinder and the cooperating components, such as cuffs or the like. The, in particular from the brake disc in the operation of the or the brake cylinder on the friction lining transferred friction heat thus no longer planted directly into the metallic back plate and thus the actuator continues, but the temperature is lower by the downstream, in particular provided in the profiles material Thermal conductivity largely compensated.

Due to the special configuration of the profiles, in particular the elevations extending only partially in the direction of the actuating element, a further decoupling of the temperature flow is realized. The arranged on a circumference segment-like elevations remain substantially within the diameter (the cross-sectional area) of the one or more actuators, so that the contact surface of the same or with the metallic back plate is limited to these segments.

According to a further aspect of the invention, the material with lower thermal conductivity is provided only in the profiles.

The metallic back plate can be both a cast plate with already molded profiles and a conventional steel back plate with corresponding impressions. The outstanding from the metallic back plate in the direction of the actuating element profiles preferably have a height <2 mm, in particular 0.5 to 1.0 mm.

• Reduzierung der Wärmeleitung;
• Reduzierung der Wärmestrahlung;
• Erhöhung der konvektiven Wärmeübertragung an die Umwelt.

The elevations associated with the profiling of the metallic back plate have the following advantages:

• Reduction of heat conduction;
• Reduction of heat radiation;
• Increase in convective heat transfer the environment.

Applicable is the subject invention preferably in all disc brakes (hydraulic and pneumatic). This solution can also according to further in the prior art US-A 6,041,893 be omitted described additional layers.

Preferred materials for the profiles or their compounds have as essential constituents:
Magnesium oxide, vermiculites, fibers, in particular PAN fibers, rock wool, recycled materials and resins, in particular phenolic resins, additions of silica and glass fibers and wollastonite are also conceivable. The following are areas for possible materials with low thermal conductivity (all figures in% by mass) magnesia 10 - 14% vermiculite 30 - 35% PAN fibers 1 - 2% rock wool 18 - 22% glass fiber 1 - 3% wollastonite 6 - 8% phenolic resin 12 - 16% Recycle material 5 - 8% silica 3 - 5%

Figur 1

Prinzipskizze einer Bremsbacke in verschiedenen Ansichten;

Figur 2

Ansicht gemäß Linie II-II der Figur 1

Figur 3

eine erfindungsgemäße Bremsbacke mit zwei Betätigungselementen

Figur 4

Darstellung segmentartiger Erhebungen auf der Rückenplatte der Bremsbacke;

Figur 5

Querschnitt durch einen Teilbereich der Bremsbacke gemäß Figur 3.

The subject invention is illustrated by means of an embodiment in the drawing and will be described as follows. Show it:

FIG. 1

Schematic diagram of a brake shoe in different views;

FIG. 2

View according to line II-II of the FIG. 1

FIG. 3

a brake shoe according to the invention with two actuators

FIG. 4

Representation of segmental elevations on the back plate of the brake shoe;

FIG. 5

Cross section through a portion of the brake shoe according to FIG. 3 ,

FIG. 1 shows a schematic diagram of a brake shoe 1, including a metallic back plate 2 and a friction lining 3, which is fixed for example by vulcanization on the back plate 2. The brake shoe 1 cooperates in this example with a brake cylinder 4 as an actuator and includes a profiling 5 in the form of a depression / elevation, the cross-sectional shape is provided substantially within the diameter d of the brake cylinder 4. The metallic back plate 2 should be in this example a steel plate, in which the profile 5 is stamped. On the friction lining side, a covering material 6 is introduced within the profile 5, which has a lower thermal conductivity than the friction material 3 itself. By this measure, the heat flow from the friction lining 3 in the direction of the metallic back plate 2 and the adjoining brake cylinder 4 can be reduced, such that in particular in the problematic area of the brake cylinder 4, the temperature transmission is inhibited. The raised area 7 of the profile 5 facing the brake cylinder 4 has a height of s = 1 mm. The profile 5 has a circular cross-sectional area ( Fig. 2 )

FIG. 3 shows a brake shoe according to the invention 1 ', including a formed in this example as a cast body back plate 2' and a friction lining 3 '. In this example, two brake cylinders 4 'are used.
FIG. 4 shows a cross section through the back plate 2 'according to section line IV -IV, being provided in the region of the brake cylinder 4' segment-like, arranged on an imaginary circle circumference profiles 5 'are provided. These profile-like, extending in the direction of the force part elevations 7 'have been molded in the production of the cast plate 2' already.
FIG. 5 shows a section along the line BB according to FIG. 4 , Recognizable is the back plate 2 ', the friction lining 3' and the introduced profiles 5 ', the reibbelagseitig are provided as a recess and kraftteilseitig as an increase 7'. Friction lining side is - as already in FIG. 1 addressed - a covering material 6 'is provided, which has a relation to the friction lining reduced thermal conductivity.
The FIGS. 2 to 5 It can be seen that the profile-like elevations 7, 7 'are provided substantially within the cross-sectional area of the respective brake cylinder 4', so that only in these areas a heat transfer from the friction lining 3 'on the back plate 2' in the direction of the brake cylinder 4 'is possible , As a result of the lining material 6 ', a heat transfer is reduced such that damage to the brake cylinder 4', respectively the cooperating components, such as protective caps or the like, can be safely avoided. In this example, the profiles have a height of 1.0 mm. The employed material 6, 6 'in these examples has the following compositions to which, however, the subject of the invention is not limited (all figures in% by mass). magnesia 12:00 vermiculite 33.00 PAN fibers 1:50 rock wool 8:00 pm glass fiber 2:00 wollastonite 7:00 phenolic resin 14:00 Recycle material 6:50 silica 4:00

Claims (4)

1. Brake pad, in particular for disk brakes, comprising a back plate (2,2') provided with profiles (5,5') to which at least one friction lining (3,3') is attached and whereby the profiles (5,5') are provided within the cross-sectional area of an activation element (4,4') and the profiles (5,5') are each formed by at least one single raised area or a corresponding depression on the side of the friction lining, wherein a plurality of profiles (5,5') having an approximately circular segment shape are disposed on a circular periphery essentially on a common radius and characterised in that a material (6,6') with a lower heat conductivity than that of the friction lining (3,3') is provided only in the profiles (5,5').
2. Brake pad according to claim 1, whereby the height of the profiles (5,5') is less than 2 mm, in particular 0.5 to 1.0 mm.
3. Brake pad according to claim 1, characterised in that the material (6,6') with lower heat conductivity comprises the following essential material components: magnesium oxide, vermiculite, fibres, such as glass fibres or PAN fibres, rock wool, wollastonite, silicic acid and resins, such as phenolic resins, as bonding agents.
4. Brake pad according to any one of claims 1 to 3, characterised in that the material (6,6') with lower heat conductivity has the following composition (in mass %): Magnesium oxide 10-14% Vermiculite 30-35 % PAN fibres 1-2% Rock wool 18-22 % Glass fibres 1-3% Wollastonite 6-8% Phenolic resin 12-16% Recycled Material 5-8% Silicic acid 3-5%

Images